1. Field of the invention
The present invention relates to a fastening device which is particularly usable for sports shoes, such as roller skates or ice skates or ski boots.
2. Description of the Prior Art
It is known to fasten the flaps of shoes by using fastening levers, associated with a first flap to be fastened, which allow one, for example, to place tension on a toothed strap which is rigidly coupled to the other flap of the shoe.
The problems that arise in the production of these devices mainly consist in having to perform optimum tensioning of the strap and to allow quick and easy release of the strap.
Italian Utility model application No. 61949 B/78, shows a partial solution to these problems: it relates to a lever-type closure device for ski boots which essentially includes a lever which is rigidly coupled to a flap of the upper and a substantially rigid toothed strap for connecting the flaps, which is pulled by the lever.
In this solution, the strap is rigidly coupled, at one end, to a flap of the upper and engages a stop ratchet system which is articulated to the closure lever.
This device, however, has drawbacks, such as the fact that the ratchet system can be actuated only once the lever has been opened, thus forcing the user to apply a considerable effort in order to overcome the degree of fastening set on the toothed strap.
Furthermore, any accidental impact of the free end of the lever with the snow or ground may entail accidental openings of the lever and a consequent loosening of the toothed strap, with a consequent unfastening of the flaps.
Italian Utility model application No. 59401B/90, discloses a device for fastening a first flap and a second flap of a shoe; the device includes a first base which is rigidly coupled to the first flap and from which there protrude two pivoting shoulders for a lever arm which has a pivot for a support provided with a ratchet system for engaging a toothed tab. The support and the ratchet system have a first longitudinal slot and a second longitudinal slot which act as a seat for the pivot, which selectively interacts with a stop means formed on the shoulders.
This device has the drawback that optimum fastening is achieved only when the strap is tensioned so as to temporarily accommodate the ends of the pivot in the stop means formed on the front perimetric edge of the pair of shoulders.